U.S. patent application number 12/803484 was filed with the patent office on 2011-02-17 for illumination device as well as observation device.
Invention is credited to Alfons Abele, Heinz Abramowsky, Daniel Kolster, Peter Reimer, Fritz Straehle.
Application Number | 20110037947 12/803484 |
Document ID | / |
Family ID | 35064819 |
Filed Date | 2011-02-17 |
United States Patent
Application |
20110037947 |
Kind Code |
A1 |
Reimer; Peter ; et
al. |
February 17, 2011 |
Illumination device as well as observation device
Abstract
Disclosed are an illumination device for an observation device
comprising one, two or more observation beam paths with one
respective beam of observation rays, especially for an
ophthalmologic surgical microscope, and a corresponding observation
device. Said illumination device is provided with at least one
light source for generating at least one beam of observation rays
in order to illuminate an object that is to be observed. According
to one embodiment of the invention, at least two partial bundles of
illumination rays are provided, each of which extends coaxial to a
corresponding beam of observation rays, while the partial beams of
illumination rays are embodied so as to form two or several
illumination spots on the fundus of an object that is to be
observed, e.g. an eye, said illumination spots having variable
sizes, thus allowing the illumination beam to cooperate in a
precisely defined manner with the observation beam paths, which
makes it possible to meet especially the practical requirements
regarding homogeneity of the red reflex.
Inventors: |
Reimer; Peter; (Ellwangen,
DE) ; Abramowsky; Heinz; (Geigen (Brenz), DE)
; Kolster; Daniel; (Oberkochen, DE) ; Straehle;
Fritz; (Heubach, DE) ; Abele; Alfons;
(Schwaebisch-Gmuend, DE) |
Correspondence
Address: |
KRIEGSMAN & KRIEGSMAN
30 TURNPIKE ROAD, SUITE 9
SOUTHBOROUGH
MA
01772
US
|
Family ID: |
35064819 |
Appl. No.: |
12/803484 |
Filed: |
June 28, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11659594 |
Feb 6, 2007 |
|
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12803484 |
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Current U.S.
Class: |
351/221 |
Current CPC
Class: |
A61B 90/30 20160201;
A61B 90/20 20160201; A61B 3/13 20130101; A61B 3/12 20130101; A61B
3/1225 20130101; A61B 90/36 20160201 |
Class at
Publication: |
351/221 |
International
Class: |
A61B 3/12 20060101
A61B003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2004 |
DE |
10 2004 038 372.3 |
Oct 18, 2004 |
DE |
10 2004 050 651.5 |
Claims
1. An illumination device for an observation device having one, two
or more observation beam paths, having an observation light bundle
for each path, having at least one light source for producing at
least one illumination light bundle for illuminating an object to
be observed, in particular, an eye to be observed, hereby
characterized in that the size of the lighting spot(s) on the
fundus of the object to be observed does not exceed 1.times.,
preferably 0.7.times., more preferably 0.5.times., most preferably
0.3.times. of the cross-sectional area of the observation light
bundle on the fundus.
2. The illumination device according to claim 1, further
characterized in that the at least one illumination light bundle
runs coaxially to the corresponding observation light bundle.
3. An observation device, in particular, an operating microscope,
having one, two or more stereoscopic observation beam paths, having
an observation light bundle for each path, and having an
illumination device, having at least one light source for producing
at least one illumination light bundle for illuminating an object
to be observed, for example, an eye, hereby characterized in that
the illumination light bundle forms at least one lighting spot on
the fundus of the object to be observed and that the size of the
lighting spot(s) on the fundus does not exceed 1.times., preferably
0.7.times., more preferably 0.5.times., most preferably 0.3.times.
of the crass-sectional area of the observation light bundle on the
fundus.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional of U.S. patent
application Ser. No. 11/659,594, inventors Peter Reimer et al.,
filed Feb. 6, 2007, the disclosure of which is incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates first to an illumination
device for an observation device according to the preamble of
patent claims 1, 7 and 9. In addition, the invention relates to an
observation device according to the preambles of patent claims 27,
28 and 29 as well as special uses according to the preambles of
patent claims 34 and 35.
[0003] For example, an observation device may involve an operating
microscope. In particular, the observation device can be designed
as an ophthalmologic operating microscope, which is utilized, for
example, for a special application in eye surgery, i.e., cataract
surgery.
[0004] In the case of cataract surgery, a lens of the eye--which is
clouded, for example, due to the cataract--is replaced by an
artificial lens.
[0005] The lens of an eye is found inside a thin envelope, the
so-called lens capsule. In order to remove the lens of the eye,
access to it is created by a thin cut made in the lens capsule and
the lens of the eye is first broken up into small pieces with a
microsurgical instrument, and then these pieces are removed by
means of an aspirating device.
[0006] This process takes place under microscopic observation--for
example, under stereomicroscopic observation--employing a specially
designed illumination device for such interventions. This
illumination device presents both an illumination of the
surrounding field, which is necessary for illuminating the entire
operating field, as well as a red background illumination for the
actual operating field limited to the pupil region of the lens of
the eye, which is of decisive importance for the cataract
operation. This red background illumination is derived from the
fraction of illuminating light, which, after passing through the
transparent media of the eye, finally strikes the retina, which
appears red due to good blood perfusion, is back-scattered
therefrom, and then can be observed, of course, as an apparent red
background illumination by the surgeon also by means of the
operating microscope. This very characteristic red background
illumination in cataract surgery is generally known in the
profession under the term "red reflex".
[0007] For an optimal recognition of details relevant to the
cataract operation, a red background illumination that is as
homogeneous as possible has been proven to be a necessary
prerequisite for the surgeon. A first requirement of the
illumination device is thus to assure a homogeneity of the red
reflex that is as optimal as possible over the entire pupil of the
patient.
[0008] For complete elimination of the pieces of the lens of the
eye which has been broken up into tiny pieces and for good
recognition of transparent membranes, for example, of the lens
capsule, another requirement must be fulfilled, that is, there must
be a good contrasting of phase objects and in fact, this contrast
should also be provided as much as possible over the entire pupil
of the patient.
[0009] In the past, various solutions have already been made known
in connection with the production of such red background
illumination.
[0010] In U.S. Pat. No. 4,779,968, a coaxial illumination for an
operating microscope is described. According to this solution, a
lighting module is provided, which can be subsequently incorporated
as an additional module in existing operating microscopes. This
additional module is preferably introduced on the object side
underneath the principal objective of the observation device. The
illumination is coupled onto the axis of the microscope either with
a beam-splitter plate or a beam-splitter cube.
[0011] An illumination device for an operating microscope is
described in DE 4,028,605 C2, which permits a combination of
zero-degree, coaxial and oblique illumination. For this purpose,
the illumination device makes available movable sub-mirrors as well
as a stationary six-degree mirror plus the respective variable
diaphragms, by which means the angle of illumination and the
lighting components of the respective illumination device can be
varied. The emphasis of this known solution lies in increasing the
contrast by means of a coaxial illumination, wherein this coaxial
illumination involves an oblique illumination found near the
axis.
[0012] An ophthalmologic observation device is disclosed in DE 196
38,263 A1, in which the unavoidable corneal reflex that occurs when
a patient's eye is illuminated for observation of the front
segments of the eye will be suppressed. This is performed by
introducing a light absorber in the form of a black point in the
vicinity of a luminous-field diaphragm of an otherwise known
illumination.
[0013] A reversible illumination system for an ophthalmologic
operating microscope is described in U.S. Pat. No. 6,011,647, in
which the system can be switched between a surrounding-field
illumination and an optimized "red reflex" illumination during the
operation. The illumination device is comprised of a light source,
a collector, a luminous-field diaphragm, a tilting mirror, a field
lens and a principal objective. In the case of this optimized "red
reflex" illumination, the helix of the light source is then imaged
or mapped in the pupil of the eye as the object plane, and not the
luminous-field diaphragm as is the case with surrounding-field
illumination.
[0014] In EP 1,109,046 A1, an illumination device for an operating
microscope is disclosed, which has two reflection elements that can
be moved independent of one another, by means of which both the
angle of the incident light with the optical axis of the microscope
objective as well as the intensity of the different light beams can
be changed independent of one another.
[0015] For surgery on the eye, and here, in particular, in cataract
operations, a homogeneous, bright "red reflex" is required along
with a good contrasting of phase objects over the entire region of
the patient's pupil.
[0016] The operating microscopes of the prior art fulfill these
requirements for regions of the pupil that are of varying size. A
compromise must always be found between the primary requirements of
a good, homogeneous "red reflex" and a good contrasting of phase
objects.
[0017] For the most part, illumination is produced at a small angle
for observation. This has the consequence, however, that the "red
reflex" does not appear uniformly bright over the patient's pupil.
An illuminating angle between 2 and 4 degrees has previously proven
favorable. At this angle, one obtains a good compromise between
good contrasting and illumination of the patient's pupil. With this
arrangement, however, the "red reflex" reacts sensitively to a
rolling of the patient's eye during the operation.
[0018] Tests with coaxial illumination in fact led to a good,
homogeneous "red reflex", but to a poor contrasting of phase
objects, and thus previously have not proven suitable in practice.
In this case, the illuminating optics were disposed such that an
illuminating mirror (or prism) lay between the two beam paths of
the stereomicroscope. In this case, therefore, a precise 0.degree.
illumination, which is accurately produced from the same direction
as the observation, was not provided.
[0019] Finally, an illumination device for operating microscopes is
described in DE 4,417,273 A1, in which the illuminating light
bundle is divided into at least two partial illuminating light
bundles, wherein each partial illuminating light bundle of the
illuminating beam runs coaxially to an illuminating light bundle.
In this way, the "red reflex" will be improved.
SUMMARY OF THE INVENTION
[0020] Starting from the named prior art, the object of the present
invention is to further develop an illumination device as well as
an observation device of the type named initially, in order to
further improve the desired optimizing. In particular, an
illumination device as well as an observation device will be
provided, with which an optimal solution to the problem of
practical requirements can be provided relative to homogeneity of
the "red reflex" and/or good contrasting of the lens pieces or
membranes, respectively, in the lens capsule.
[0021] According to the invention, this object is solved by the
illumination device with the features according to the independent
patent claims 1, 7 and 9, the observation device with the features
according to independent patent claims 27, 28 and 29 as well as the
special uses according to independent patent claims 34 and 35.
Other advantages, features, details, aspects and effects of the
invention result from the subclaims, the description, as well as
the drawings. Features and details that are described in connection
with the illumination device according to the invention, thus also
apply, obviously, in connection with the observation device
according to the invention and vice versa. The same is true for the
particular uses.
[0022] According to the first aspect of the invention, an
illumination device is provided for one, two or more--particularly
stereoscopic--observation beam paths, with an observation device
having an observation light bundle for each path, having at least
one light source for producing at least one illumination light
bundle for illuminating an object to be observed, in particular, an
eye to be observed, wherein at least two partial illumination light
bundles are provided and wherein each partial lighting illumination
bundle runs coaxially to a corresponding observation light bundle.
The illumination device is hereby characterized according to the
invention in that the partial illumination light bundles are/will
be formed in such a way that they form two or more lighting spots
that are variable in size on the fundus of an object to be
observed, for example, an eye.
[0023] The essence of the present invention thus first lies in a
new conception of the illumination device. The new conception of
the illumination device, among other things, consists of the fact
that the latter produces at least two light bundles originating
from one or even several light sources, wherein the optical axes of
these light bundles run coaxially to the optical axes of the
observation light bundles.
[0024] For example, a single light source can be provided, which
first produces a single illumination light bundle. This
illumination light bundle is subsequently divided into the desired
number of partial illumination light bundles by suitable means, for
example, beam splitters or the like. For example, it may also be
provided, however, that the illumination device has two or more
light sources, wherein each light source then produces one partial
illumination light bundle.
[0025] In this way, a true coaxial illumination is created.
"Coaxial" is therefore generally an illumination near the axis.
This includes both an illumination under precisely zero degree as
well as an oblique illumination at a very small angle near the
axis. This could be denoted as "substantially coaxial". Examples of
this are explained in more detail in the further course of the
description.
[0026] The new illumination concept of at least two coaxial partial
illumination light bundles, according to the invention, produces
two or more lighting spots that are variable in size on the fundus
of the object to be observed, for example, an eye.
[0027] The invention is not limited to a specific size or shape of
the lighting spots. Advantageously, the lighting spots can have a
round or approximately round geometry. Other geometries are also
conceivable, however, i.e., elliptical, polygonal, annular lighting
spots and similar shapes.
[0028] Then, in addition to a homogeneous "red reflex", a good
contrasting of phase objects is also obtained by a neat,
diffraction-limited imaging of the (secondary) light source onto
the fundus.
[0029] Advantageously, the diameter of the lighting spots can be
varied in a range between 0.5 and 1.5 mm on the fundus of the
object to be observed. Of course, the lighting spots may also have
a larger or smaller diameter. Advantageously, the diameter of the
lighting spot(s) can be formed such that it does not exceed 1.5 mm,
preferably 1.0 mm, and more preferably 0.5 mm, on the fundus of the
object to be observed.
[0030] The variation in the diameter of the lighting spot is thus
caused by a variation of the partial illumination light bundle.
[0031] Advantageously, the illumination light bundles can be/will
be able to be formed such that the size of the lighting spot on the
fundus of the object to be observed does not exceed 1.times.,
preferably 0.7.times., more preferably 0.5.times., most preferably
0.3.times. of the cross-sectional area of the observation light
bundle on the fundus.
[0032] The variation of the diameter of the lighting spot can be
produced in different ways. Advantageously, this is done with the
help of diaphragms, for example discrete diaphragms with different
diameters or variable diaphragms with variable diameters (iris
diaphragms). It is also conceivable, however, to utilize suitable
displays for this purpose, for example, LCD displays. Likewise, it
is possible to produce variation by means of a suitable zoom
system. The last-named variant has the additional advantage that
the light intensity increases in the lighting spot, if the diameter
of the lighting spot is made smaller.
[0033] The intensity (brightness) and the homogeneity of the "red
reflex" can be influenced by the variation of the lighting spot on
the fundus of an object to be investigated. The greater the
diameter is selected for the lighting spot, the more homogeneous
and brighter is the "red reflex". The smaller the diameter is
selected for the lighting spot, the better is the contrasting of
the "red reflex". The suitable diameter of a lighting spot is now
freely adjustable, depending on need and case of application each
time.
[0034] With an illumination device according to the present
invention, a precise coaxial illumination is produced, which
supplies a homogeneous "red reflex", and which is also still
insensitive to a rolling of the object to be observed, for example,
a patient's eye. In this way, a possible readjustment of the
illumination for optimizing the "red reflex" when the eye rolls can
also be dispensed with, whereby the construction of the
illumination device or of a corresponding observation device is
simplified.
[0035] According to the invention, the illumination device is
provided for an observation device, but the invention is not
limited to specific types of observation devices. For example, but
not exclusively, however, the observation device may involve an
operating microscope. Several non-exclusive examples for possible
application purposes in the field of operating microscopes are
described in detail in connection with the observation device
according to the invention.
[0036] Particularly advantageously, the illumination device
according to the invention can be utilized as a 0.degree.
illumination system--in particular, a dual system--for an operating
microscope for application in ophthalmic surgery.
[0037] According to an advantageous configuration, each partial
illumination light bundle is guided in such a way that an object to
be observed is/will be illuminated from the same direction, with
respect to each observation light bundle, from which the
observation is also produced (0.degree. observation). If the
observation device involves a (stereo) operating microscope, each
partial illumination light bundle is guided in such a way that the
object to be observed--for example, an eye--is illuminated from the
same direction from which the observation is also made, for the
left and right observation beam paths of the (stereo) operating
microscope. Therefore, a precise 0.degree. illumination is present
for each observation beam path.
[0038] According to another advantageous configuration, each
partial illumination light bundle is guided in such a way that an
object to be observed relative to each observation light bundle
is/will be illuminated obliquely at an angle of less than/equal to
2 degrees, preferably less than/equal to 1 degree (oblique
illumination near the axis). The object to be investigated will be
illuminated at a small angle for observation.
[0039] An optimal "red reflex" with simultaneous good contrasting
is obtained by a neat, diffraction-limited guidance of the light
beam for the illumination and small lighting spots on the fundus of
a patient's eye. Further, this illumination device reacts very
non-critically to a rolling of the patient's eye during the
operation.
[0040] A particularly advantageous embodiment of the invention
provides an illumination device for one, two or more observation
beam paths, with an observation device having an observation light
bundle for each path, with at least one light source for producing
at least one illumination light bundle for illuminating an object
to be observed, in particular, an eye to be observed, whereby each
observation light bundle or partial observation light bundle,
respectively, runs coaxially or at least substantially coaxially to
the corresponding observation light bundle, whereby the size of the
lighting spot(s) on the fundus of the object to be observed does
not exceed 1.times., preferably 0.7.times., more preferably
0.5.times., most preferably 0.3.times. of the cross-sectional area
of the observation light bundle on the fundus. In an advantageous
enhancement, it can be further provided that the diameter of the
lighting spot(s) on the fundus does not exceed 1.5 mm, preferably
1.0 mm, and more preferably 0.5 mm.
[0041] According to another aspect of the invention, an
illumination device is provided for an observation device having
one, two or more stereoscopic observation beam paths, with an
observation light bundle for each path, having at least one light
source for producing at least one illumination light bundle for
illuminating an object to be observed, in particular, an eye to be
observed. The illumination device is characterized according to the
invention in that the illumination light bundle is imaged in a
diffraction-limited manner and that the illumination light bundle
forms one or more lighting spots that are variable in size on the
fundus of the object to be observed.
[0042] In the simplest case, according to this aspect, a single
illumination light bundle is provided, which produces a single
lighting spot. Embodiments having two or more illumination light
bundles are also possible, however, whereby in each case, one
illumination light bundle produces one lighting spot. In the
last-named case, the illumination light bundles--when considered in
their totality--each represent a partial illumination light
bundle.
[0043] For the configuration of the illumination device according
to the invention, reference is also made to the preceding
embodiments for the first aspect of the invention.
[0044] It can be advantageously provided that the size of the
lighting spot(s) on the fundus of the object to be observed does
not exceed 1.times., preferably 0.7.times., more preferably
0.5.times., most preferably 0.3.times. of the cross-sectional area
of the observation light bundle on the fundus.
[0045] According to another aspect, an illumination device is
provided for an observation device having one, two or more
observation beam paths, with an observation light bundle for each
path, having at least one light source for producing at least one
illumination light bundle for illuminating an object to be
observed, in particular, an eye to be observed. It can be provided
according to the invention that the size of the lighting spot(s) on
the fundus of the object to be observed does not exceed 1.times.,
preferably 0.7.times., more preferably 0.5.times., most preferably
0.3.times. of the cross-sectional area of the observation light
bundle on the fundus.
[0046] Advantageously, at least one illumination light bundle may
run coaxially to the corresponding observation light bundle.
[0047] In another configuration, it is advantageously provided that
the distance of the center of the lighting spot from the center of
the cross-sectional area of the observation light bundle on the
fundus amounts to 0.8.times., preferably 0.5.times., more
preferably 0.2.times., most preferably 0.05.times. of the radius of
the cross-sectional area of the observation light bundle on the
fundus.
[0048] By the illumination device according to the present
invention, it can be achieved, in particular, that the optimal size
of the lighting spot is aligned to the refractive error of the
patient and the magnification of the observation device, for
example, an operating microscope. This is achieved, for example, by
the relative data of the size of the lighting spot relative to the
cross-sectional area of the observation light cone on the fundus.
The essential features for an optimal red reflex are realized,
i.e., small spot size for good contrast, as well as the position of
the lighting spot on the fundus.
[0049] An advantageous embodiment of the invention provides an
illumination device for an observation device having one, two or
more observation beam paths, having an observation light bundle for
each path, having at least one light source for producing at least
one illumination light bundle for illuminating an object to be
observed, in particular, an eye to be observed, whereby the size of
the lighting spot(s) on the fundus of the object to be observed
does not exceed 1.times., preferably 0.7.times., more preferably
0.5.times., most preferably 0.3.times. of the cross-sectional area
of the observation light bundle on the fundus, and whereby the
distance of the center of the lighting spot from the center of the
cross-sectional area of the observation light bundle on the fundus
amounts to 0.8.times., preferably 0.5.times., more preferably
0.2.times., most preferably 0.05.times. of the radius of the
cross-sectional area of the observation light bundle on the
fundus.
[0050] Advantageously, the diameter of the at least one lighting
spot can be varied in a range between 0.5 and 1.5 mm on the fundus
of the object to be observed. Advantageously, the diameter of the
lighting spot(s) can be formed such that it does not exceed 1.5 mm,
preferably 1.0 mm, and more preferably 0.5 mm on the fundus of the
object to be observed.
[0051] Advantageously, the illumination device according to the
invention can have at least one objective element. The objective
element can also be formed as an objective element of an
observation device, in particular as its principal objective.
However, this is not absolutely necessary.
[0052] In addition, different optical elements, which are disposed
between the at least one light source and the at least one
objective element, can be provided in the illumination device.
[0053] In an advantageous configuration, means are provided in
order to superimpose an observation light bundle on a partial
illumination light bundle or, respectively, the illumination light
bundle. These means can be configured in the most diverse way and
disposed at the most diverse sites. Several nonexclusive examples
will be explained below for this purpose.
[0054] For example, it may be provided that the means for
superimposing are disposed in such a way that a superimposition of
the observation light bundle on a partial illumination light bundle
or the illumination light bundle is made above the objective
element. The superimposition of the observation light bundle on a
partial illumination light bundle or the illumination light bundle
can be made, for example, in the parallel beam path above the
principal objective.
[0055] For example, it may be provided that the means for
superimposing are disposed in such a way that a superimposition of
the observation light bundle on a partial illumination light bundle
or the illumination light bundle is made underneath the objective
element. The possibility thus also exists of superimposing a
partial illumination light bundle or the illumination light bundle,
respectively, on the observation light bundle underneath the
principal objective. It is advantageous in this case, if the
partial illumination light bundles are inclined, corresponding to
the focal depth of the principal objective.
[0056] Advantageously, it may be particularly provided in the
last-named case that the objective element is formed as a so-called
varioscope optics. A varioscope optics generally involves an optics
with at least two optical elements separated by a distance, wherein
the free working distance between objective and object plane can be
varied by variation of this distance. Such a varioscope optics is
already known in and of itself from the prior art. In the
above-described case, with superimposition of the light bundles
underneath the objective element, it is advantageous, when a
varioscope optics is used, if the partial illumination light
bundles are re-adjusted corresponding to the free working
distance.
[0057] As has been stated above, the invention is not limited to
specific types of configurations of "superimposition means". For
example, the means for superimposing can have at least one optical
element in the form of a prism and/or a beam splitter plate and/or
a mirror, e.g., a semi-reflecting mirror and/or a perforated
mirror. Of course, the means can be configured in another way, so
that the invention is not limited to the named examples.
[0058] In another configuration, it can be provided that means are
provided in order to produce at least one annular partial
illumination light bundle, which is disposed around an observation
light bundle.
[0059] Advantageously, at least one device for changing the cross
section of the bundle of the at least one illumination light bundle
and/or at least one partial illumination light bundle can be
provided. In such a case, the invention is not limited to specific
embodiments of the device. The device can be designed, for example,
as a diaphragm, in particular, an iris diaphragm or a discrete
diaphragm, as an LCD (liquid crystal display) display, as a DMD
(digital mirror device), as an LCOS (liquid crystal on silicon), as
an FLCOS (ferroelectric liquid crystal on silicon), or similar
device. By incorporating an appropriate device in the illumination
device, e.g., in the illumination beam, it is possible to vary the
light spot on the surface of the object to be observed, for
example, on the fundus of the patient's eye. A small light spot
supplies a better contrast. In cataract surgeries, it may be the
case that the "red reflex" can appear too dark, particularly in the
case of dense cataracts. Here, it is of advantage to enlarge the
light spot and thus increases the brightness. The intensity of the
radiation on the retina will not be increased thereby. Negative
effects on contrast are not to be expected, since in the case of a
very dense or thick cataract, the light spot is scattered without
anything further.
[0060] Another advantage of the illumination device according to
the invention consists of the fact that only a corneal reflex will
be visible on the cornea-front surface of the patient's eye, since
the partial illumination light bundles are approximately overlapped
or masked at this site.
[0061] In an advantageous configuration, it can be provided that
two or more light sources are provided and that a partial
illumination light bundle will be produced by means of each light
source. Thus independent light sources can be used, whereby each
light source produces its own partial illumination light
bundle.
[0062] In another advantageous configuration, it can be provided
that a single light source is provided and that means for splitting
the illumination light bundle of the light source into two or more
partial illumination light bundles are provided. Here, suitable
beam splitters in the form of prisms, semi-reflecting mirrors and
similar means can be used.
[0063] The present invention is not limited to the use of specific
light sources. Several nonexclusive, advantageous examples will be
named below for this purpose. For example, the at least one light
source can be formed as a lamp, in particular as a halogen lamp or
a xenon lamp, as a laser, as a non-thermal radiator, as a light
guide, in particular as an optical-fiber light guide bundle, as at
least one LED (light-emitting diode), as at least one OLED (organic
light-emitting diode), or similar source. Of course, combinations
of different light sources are also possible.
[0064] Advantageously, the light source is formed of an arrangement
of one or more micro light source(s) that can be switched on
individually or by regions. The illumination device is configured
such that it can be varied in a simple manner with respect to the
geometry of the light field that it produces. In this way, the
micro light sources will be controlled--in particular,
electronically--from the outside, preferably by a control device.
Another feature provides that the micro light sources can be
controlled, at least in regions, in order to be able to adjust
variable lighting geometries. This is particularly of advantage in
the case of the generation of annular partial illumination light
bundles. In this case, the invention is not limited to specific
sizes and/or shapes of regions. In the simplest case, a single
point can be controlled in such a way. Particularly when the
luminous source is formed from a matrix comprised of individual
micro light sources, one or more micro light sources can be
controlled individually or in groups, whereby in the last-named
case, individual micro light sources can be combined into one
region. Also, in this respect, the invention is not limited to
concrete configurations.
[0065] Advantageously, the light source can be formed of an
arrangement of one or more light diode(s) (LEDs), in particular
organic light diode(s) (OLEDs). Organic light diodes were
originally developed as microdisplays. Unlike LCDs, which require a
backlighting, OLEDs by themselves illuminate as Lambert radiators
(surface or flat emitters).
[0066] As patterned lighting sources, OLEDs offer a good light
efficiency and small structures without intermediate dark spaces.
Depending on the desired lighting geometry, individual micro light
sources can be turned on and others can be turned off. The filling
factor is higher in OLEDs as opposed to LEDs, which means that a
higher packing density can be realized. The use of a display of
LEDs or OLEDs makes possible a programmable, and also, for example,
an automatable switching of different lighting modes, without
having to move mechanical components, such as, e.g., phase contrast
rings, filters, reducers and similar components. Particularly
suitable, for example, are white OLEDs, whose spectrum is
determined by a mixture of organic molecules.
[0067] In summary, the illumination device described above has a
large number of advantages. A very homogeneous and bright "red
reflex" can be produced by a coaxial lighting, in particular by a
"true" 0.degree. illumination. The "red reflex" reacts very
insensitively to a tilting of the object to be observed, for
example a patient's eye. That is, a readjustment relative to angles
can be dispensed with. By integrating a device for changing the
cross section of the light bundle, for example, a (double) iris
diaphragm, the brightness of the "red reflex" and the contrast of
phase structures can be adapted and optimized to the treatment
situation. The contrast will be improved by reducing the diameter
of the iris diaphragm, but, of course, the brightness will also
decrease.
[0068] According to another aspect of the invention, an observation
device is provided, in particular an operating microscope, having
one, two or more stereoscopic observation beam paths, having an
observation light bundle for each path, and having an illumination
device, having at least one light source for producing at least one
illumination light bundle for illuminating an object to be
observed, in particular, an eye to be observed. The illumination
device has--adapted to stereoscopic observation--at least two
partial illumination light bundles, wherein each partial
illumination light bundle runs coaxially to a stereoscopic
observation light bundle. According to the invention, it is
provided that the partial illumination light bundles are formed in
such a way that they form two or more lighting spots that are
variable in size on the fundus of an object to be observed.
[0069] According to another aspect of the invention, an observation
device is provided, in particular an operating microscope, having
one, two or more stereoscopic observation beam paths, having an
observation light bundle for each path, and having an illumination
device, having at least one light source for producing at least one
illumination light bundle for illuminating an object to be
observed, for example, an eye. This observation device is hereby
characterized according to the invention in that the illumination
light bundle is imaged in a diffraction-limited manner and that the
illumination light bundle forms one or more lighting spots that are
variable in size on the fundus of the object to be observed.
[0070] According to another aspect of the invention, an observation
device is provided, in particular an operating microscope, having
one, two or more stereoscopic observation beam paths, having an
observation light bundle for each path and having an illumination
device, having at least one light source for producing at least one
illumination light for illuminating an object to be observed, for
example, an eye. This observation device is hereby characterized
according to the invention in that the illumination light bundle
forms at least one lighting spot on the fundus of the object to be
observed and that the size of the lighting spot(s) on the fundus
does not exceed 1 X, preferably 0.7.times., more preferably
0.5.times., most preferably 0.3.times. of the cross-sectional area
of the observation light bundle on the fundus.
[0071] Advantageously, the diameter of the at least one lighting
spot can vary in a range between 0.5 and 1.5 mm on the fundus of
the eye to be observed. Advantageously, the diameter of the
lighting spot(s) can be formed such that it does not exceed 1.5 mm,
preferably 1.0 mm, and more preferably 0.5 mm on the fundus of the
object to be observed.
[0072] Advantageously, the illumination device is constructed in
the way described above, according to the invention, so that
reference is made here to the corresponding descriptions.
[0073] The observation device may have, for example, a principal
objective element, which is identical to an objective element of
the illumination device. In addition, means can be provided in
order to superimpose an observation light bundle on a partial
illumination light bundle or, respectively, the illumination light
bundle. The means for superimposing can be disposed in such a way
that a superimposition of the observation light bundle on a partial
illumination light bundle or the illumination light bundle,
respectively, is made above the principal objective element.
[0074] In another configuration, it may be provided that the
observation device has a principal objective element that is
identical to an objective element of the illumination device, that
means are provided in order to superimpose an observation light
bundle on a partial illumination light bundle or, respectively, an
illumination light bundle and that the means for superimposing are
disposed in such a way that a superimposition of the observation
light bundle on a partial illumination light bundle or the
illumination light bundle, respectively, is made underneath the
principal objective element.
[0075] For the last-named case, it may be advantageously provided
that the principal objective element is formed as a so-called
varioscope optics. For the configuration and mode of operation of
the varioscope optics, reference is made to the corresponding
description given above in connection with the illumination device
according to the invention.
[0076] Advantageously, the observation device can be formed as a
stereoscopic observation device, in particular as a
stereomicroscope. The optical system of an operating microscope
basically consists of several structural elements, such as the
tube, the basic body of the microscope, etc. Additionally, it is
possible in many operating microscopes to connect various
additional modules, such as, for example, a co-observer tube for an
assistant observer, a video camera for documentation or similar
units.
[0077] Several assemblies can also be combined inside the base body
of the microscope, such as, for example, an illumination device, a
magnification device, the principal objective, or similar
components. The characteristic dimension for the principal
objective is its focal depth, which establishes the working
distance from the operating microscope to the surgical field and
also has an influence on the total magnification of the
microscope.
[0078] Preferably, a magnification system can be provided in the at
least one observation beam path. For example, this may involve a
magnification changing device, with which different magnifications
can be adjusted. In many cases of application, one stepwise
magnification change is fully sufficient. However, it is also
possible to use pancratic magnification systems as the
magnification system, by means of which a step-free magnification
(zoom system) is possible. In this way, it may be advantageously
provided that the device pupil of the observation device, which has
already been described further above, is permanently disposed in
the magnification system.
[0079] In addition, a tube element and an eyepiece element can be
provided in the at least one observation beam path. The task of an
eyepiece element is generally the post-magnification of the
intermediate image forming in the tube, as well as perhaps
compensating for the possible refractive error of the user of such
a microscope.
[0080] In addition, it is advantageously provided that the object
plane of the object to be investigated is formed at the front focal
point of the principal objective. It is achieved in this way that
the object to be investigated is imaged infinitely by the principal
objective.
[0081] Advantageously, the observation device can be formed as a
stereoscopic observation device, in particular as a
stereomicroscope. In this case, the observation device provides two
observation beam paths running in parallel.
[0082] The observation device may involve a stereomicroscope
according to the telescopic principle according to a preferred
embodiment, which is essentially comprised of the three optical
sub-components, i.e., a principal objective (afocal), a zoom system
as well as a binocular telescopic device consisting of tube and
eyepiece.
[0083] The observation light bundles run between the individual
sub-components of the observation device, preferably in parallel,
so that the individual sub-components can be exchanged and combined
in modular manner.
[0084] In a preferred way, an illumination device according to the
invention as described above can be used in an operating
microscope, in particular in an ophthalmologic observation device,
preferably in an operating microscope designed for cataract
extraction. Likewise, an observation device according to the
invention as described above can be used as an ophthalmologic
observation device, preferably as an operating microscope
configured for cataract extraction.
[0085] According to the present invention, in particular, the basic
requirements in principle have been established for an optimized
illumination system in cataract surgery, i.e., a coaxial
illumination for homogeneity of the red reflex, and a stigmatic,
diffraction-limited imaging of the well-defined lighting spot for
good contrasting of the red reflex.
[0086] For example, a prism system is proposed for producing the
coaxial illumination light bundles. The size of the lighting spot
on the fundus can be adjusted in a targeted manner by suitable
adaptation of aperture diaphragms in the prism system.
[0087] In addition, the illumination system according to the
invention permits a simple switching between the optimized red
reflex illumination and the surrounding-field illumination that can
be indispensable for practical application, for complete
illumination of the maximum visual field for stereoscopic
observation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0088] The invention will now be explained in more detail based on
embodiment examples with reference to the attached drawings.
Here:
[0089] FIG. 1 shows in schematic representation one possible
arrangement for producing a 0.degree. illumination, with
simultaneous optimal "red reflex" and good contrasting.
[0090] FIG. 2 shows in schematic representation the structure of an
optical system for red reflex illumination;
[0091] FIG. 3 shows in schematic representation the structure of an
optical system for surrounding-field illumination; and
[0092] FIG. 4 shows in schematic representation the structure of
one advantageous aperture diaphragm, as it is utilized in the
illumination device according to FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
[0093] Parts of an illumination device, which is utilized in an
observation device, are shown in FIG. 1. The observation device
involves a stereo operating microscope for use in ophthalmic
surgery, for example, for conducting cataract operations. A very
uniform, bright "red reflex" is obtained by means of the
illumination device by splitting the illumination light bundle 12
into several partial illumination light bundles 13. This is
performed by means 11 for splitting the illumination light bundle,
which may provide a suitable mirror/prism arrangement for this
purpose. The partial illumination light bundles 13 are thus guided
in such a way that the object to be observed, in the present case,
a patient's eye, is illuminated from the same direction from which
the observation is also produced (0.degree. illumination), relative
to the left and right observation beam paths of the operating
microscope.
[0094] As can be taken from the left-hand side of the figure,
observation beam paths both for a principal observer (PO) as well
as also for a co-observer (CO) are provided in the example shown.
Means 11 for splitting the illumination beam path may be disposed,
for example, in the region of an objective element 10, which means
may also involve, for example, the principal objective of the
observation device.
[0095] An optimal "red reflex" with simultaneous good contrasting
is obtained with this arrangement by a neat, diffraction-limited
guidance of the beam for the illumination and small lighting spots
on the fundus of the patient's eye (diameter of approximately 0.5
to 1.5 mm). Further, this lighting arrangement reacts very
non-critically to a rolling of the patient's eye during the
operation.
[0096] The superimposing of the observation light bundle on a
partial illumination light bundle 13 can be provided, for example,
in the parallel beam path above the objective element 10 (the
principal objective) by means 11, which advantageously involves
semi-reflecting mirrors or prisms.
[0097] Further, a device 14 in the form of an iris diaphragm is
provided in the illumination device for changing the cross section
of the light bundle. In this way, the luminous spot in the
illumination light bundle 12 can be varied on the fundus of the
patient's eye.
[0098] In the present example, the illumination light bundle 12 is
produced by a single light source (not shown) and split into
several partial illumination light bundles 13 via means 11. It is
also conceivable, however, to use several light sources that are
independent of one another, whereby each light source produces at
least one partial illumination light bundle 13 each time.
[0099] The structure of the optical system for the red reflex
illumination is diagrammed in FIG. 2. The following optical
components are used, considered starting from a light source in the
illumination device 20 which is indicated: a light guide 21, a
collector 22, a plano-convex lens 23, a luminous-field diaphragm
24, an aperture diaphragm (pin diaphragm) 25, an optical component
26, for example, a sub-components comprised of a cemented member
and meniscus lens, a deflecting element 27, for example, in the
form of a separator mirror as well as an objective element 28, for
example, in the form of a principal objective. An eye 29 with
fundus 30 will be illuminated.
[0100] A real intermediate image is produced from the fiber end of
light guide 21 with collector 22 and plano-convex lens 23. Aperture
diaphragm 25, e.g., in the form of a pin diaphragm, can be
introduced at the site of this intermediate image. This real
intermediate image lies in the front focal plane of a two-member
sub-optics component comprised of the principal objective 28 and
the sub-component 26 comprised of a cemented member with meniscus
lens. This sub-optics component then forms another virtual
intermediate image in infinity, so that, considered from eye 29,
the end of the fiber of light guide 21 lies at the far point.
Consequently, the fiber end of the light guide 21 is imaged as a
lighting spot on the fundus 30 for an eye with correct vision.
[0101] The effective luminous area of the fiber end of the light
guide 21 may amount to 4.8 mm, for example. The diameter of the
intermediate image in the aperture diaphragm 25 then amounts to 5.8
mm. In the named example, a diameter of 1.5 mm is obtained for the
size of the lighting spot on fundus 30.
[0102] By means of pin diaphragms of well-defined position, the
light bundles coaxial to the stereoscopic axes of observation that
are necessary for the good homogeneity of the red reflex can be
produced in the intermediate image plane (aperture diaphragm), at
the distance of the stereo base of the stereoscopic axes of
observation. The pin diaphragms are imaged with the same imaging
scale factor as the real intermediate image of the end of the
fiber, i.e., 5.8:1.5=3.9:1, reduced on the fundus, relative to
their position, i.e., lateral displacement to the optical axis, and
their size, i.e., diameter of the pin diaphragms. The size of the
diameter of the pin diaphragms then determines the size of the
lighting spot on the fundus and thus, in a decisive manner, the
good contrasting of the red reflex.
[0103] The luminous-field diaphragm 24 is found between the
plano-convex lens 23 and the real intermediate image of the end of
the fiber (aperture diaphragm). This luminous-field diaphragm 24
serves for defining the illuminated visual field.
[0104] The luminous-field diaphragm 24 lies at the front focal
point of the sub-component 26 comprised of a cemented member and
meniscus lens. The luminous-field diaphragm 24 is thus first
virtually imaged to infinity on the object plane found at the front
focal plane of the principal objective by the sub-component 26, and
finally with principal objective 28.
[0105] The diameter of the luminous-field diaphragm 24 amounts to
2.5 mm, for example. This leads to an illuminated visual field in
the object plane of 10 mm. Therefore, the imaging scale factor
amounts to 1:4 for the luminous-field imaging.
[0106] The optical system data for the red-reflex illumination are
listed in Table 1:
TABLE-US-00001 TABLE 1 System data for red-reflex illumination
system Free Thickness of the diameter No. Radius (mm) light guide
(mm) Medium (mm) 4.7 air 1 -49.759 8.5 5.0 NSK2 2 -17.655 10.8 0.1
air 3 -37.047 11.0 2.0 NSF6 4 26.227 12.2 5.5 NSK2 5 -12.589 13.6
2.0 air 6 6.6355 5.0 2.0 NSK2 7 planar 5.0 1.9 air 8 planar
Diaphragm 13.1 air 9 planar Diaphragm 29.2 air 10 -58.984 26.0 5.0
NSK2 11 -28.387 27.0 0.1 air 12 392.42 28.0 3.0 NSF6 13 45.316 29.0
7.0 NSK2 14 -55.033 29.0 40.0 air 15 planar mirror 17.0 air 16
120.57 53.0 10.5 NFK51 17 -79.719 53.0 5.1 NBAF4 18 -244.06 53.0
188.3 air 19 8.0 6.0 BAK4 20 planar Model eye 15.4 BK7 Fundus
[0107] The structure of the optical system for the
surrounding-field illumination is diagrammed in FIG. 3.
[0108] An essential concept consists of the fact that the
surrounding-field illumination can be derived by means of a simple
switching process from the red-reflex illumination without
additional optical components.
[0109] Except for the size of the luminous-field diaphragm, the
optical components necessary for the surrounding-field illumination
are thus identical to the optical components of the red-reflex
illumination according to FIG. 2, i.e.: light guide 21, collector
22, luminous-field diaphragm 24, optical component 26, for example,
in the form of a sub-component comprised of a cemented member and
meniscus lens, deflecting element 27, for example, in the form of a
separator mirror as well as objective element 28, for example, in
the form of a principal objective.
[0110] When switching from red-reflex illumination to
surrounding-field illumination, the plano-convex lens and the
perforated lens (see FIG. 2) are swung out. In addition, a small
luminous-field diaphragm is replaced by a large luminous-field
diaphragm 24.
[0111] The luminous-field diaphragm 24 is now completely
illuminated with collector 22. The luminous-field diaphragm 24
still sits unchanged, as in the case of red-reflex illumination, in
the front focal plane of the sub-component 26 comprised of a
cemented member and meniscus lens. The luminous-field diaphragm 24
is thus virtually infinitely imaged, so that as in the case of the
red-reflex illumination, the image of luminous-field diaphragm 24
again lies in the front focal plane of principal objective 28, by
imaging with principal objective 28, and thus lies in the object
plane of the observation.
[0112] The diameter of the luminous-field diaphragm 24 amounts to
14 mm, for example. Therefore, an illumination of the maximum
visual field 31 of approximately 62 mm can be achieved in the
object plane. The magnification of the scale factor in comparison
to the red-reflex illumination can be clarified by distorting the
luminous-field image.
[0113] The optical structure for the red-reflex illumination
proposed here makes possible an independent engagement in the beam
paths for the pupil image and the luminous-field image. Thus, for
example, the light power can be optimally adapted to the size of
the luminous field, and the size of the lighting spot on the fundus
can be adapted by targeted adjustment of the aperture
diaphragm.
[0114] In the case of surrounding-field illumination, the optical
presentation of the problem is reduced on the image of the
optimally illuminated luminous-field diaphragm.
[0115] Due to the optical structure, for the pupil image, there
necessarily results a real intermediate image of the end of the
fiber in the vicinity of the front surface of the principal
objective. Usually, and also in the case of illumination currently
utilized for ophthalmology, this real intermediate image lies in
the object space, and in fact, approximately 50 mm underneath the
principal objective.
[0116] The optical system data for the surrounding-field
illumination are listed in Table 2:
TABLE-US-00002 TABLE 2 System data for surrounding-field
illumination system Thickness of the Free No. Radius (mm) light
guide (mm) Medium diameter (mm) 4.7 air 1 -49.759 8.5 5.0 NSK2 2
-17.655 10.8 0.1 air 3 -37.047 11.0 2.0 NSF6 4 26.227 12.2 5.5 NSK2
5 -12.589 13.6 5.9 air 6 planar Diaphragm 42.3 air 7 -58.294 26.0
5.0 NSK2 8 -28.387 27.0 0.1 air 9 392.42 28.0 3.0 NSF6 10 45.316
29.0 7.0 NSK2 11 -55.033 29.0 40.0 air 12 planar mirror 17.0 air 13
120.57 53.0 10.5 NFK51 14 -79.719 53.0 5.1 NBAF4 15 -244.06 53.0
193.6 air Visual field
[0117] It may also be meaningful overall to simultaneous provide
the user with red-reflex illumination and surrounding-field
illumination. This can be provided, for example, by cementing the
plano-convex lens 23 between the collector 22 and the diaphragms
24, 25, either onto a transparent support, or, for example, forming
it as an injection-molded plastic part (PMMA) with a corresponding
transparent support edge. The light rays that pass through the
plano-convex lens 23 produce the red-reflex illumination, while the
light rays that pass through the support or support edge produce
the surrounding-field illumination.
[0118] It is also advantageous to configure the aperture diaphragm
25 (pin diaphragm) in a particular manner in order to
simultaneously produce red-reflex illumination and
surrounding-field illumination. An example of this is shown in FIG.
4.
[0119] According to FIG. 4, the aperture diaphragm 25 can be
advantageously configured in such a way that the openings 25a for
red-reflex illumination can have, for example, a high transmission,
while the surrounding region 25b can have a reduced transmission
(which is adjustable in the ideal case) for the surrounding-field
illumination.
[0120] This can be realized, for example, by means of a
transmissive or reflective LCD display 25c, or by means of a DMD
display.
LIST OF REFERENCE NUMBERS
[0121] 10 Objective element [0122] 11 Means for splitting the
illumination light beam [0123] 12 Illumination light bundle [0124]
13 Partial illumination light bundle [0125] 14 Device for changing
the cross section of the light bundle [0126] 20 Illumination device
[0127] 21 Light guide [0128] 22 Collector [0129] 23 Plano-convex
lens [0130] 24 Luminous-field diaphragm [0131] 25 Aperture
diaphragm [0132] 25a Opening [0133] 25b Surrounding region [0134]
25c Display [0135] 26 Optical component [0136] 27 Deflecting
element [0137] 28 Objective element [0138] 29 Eye [0139] 30 Fundus
[0140] 31 Visual field
* * * * *